JP2008058846A - Optical device with optical filter, and projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical device with an optical filter capable of maintaining the clearness of an image without enlarging the size of the device and requiring an additional cooling means, and to provide a projector. <P>SOLUTION: The optical filter 5 for reducing components other than red color, green color and blue color from light from a light source lamp has a curvature surface 5a. Reflection light 7 on a liquid crystal display element 3 returns to the optical filter 5, re-reflection light 9 on the curvature surface 5a of the optical filter 5 is not condensed on the position of the liquid crystal display element 3, an influence of the re-reflection light is reduced and, accordingly, the clearness of the image can be maintained. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical device and a projector provided with an optical filter.

  2. Description of the Related Art In recent years, sharpening of an image has been promoted in a projector that modulates an input video signal with a light modulation device such as a liquid crystal display element and projects an optical image on a screen. An optical filter for reducing yellow and cyan light, which is an intermediate color between red, green, and blue light, is provided inside as a means.

  FIG. 4 is a plan view showing a configuration of a projector provided with an optical filter, where 1 is a light source lamp, 2 is an optical filter for reducing components other than red, green, and blue from light from the light source lamp, and 3 is A liquid crystal display element, which is a light modulation device that modulates an input video signal, 4 represents a projection lens, and 6 represents an optical axis. In the figure, the light emitted from the light source lamp 1 is transmitted through the optical filter 2 with red, green, and blue light, and yellow and cyan light are reflected. The red, green, and blue light that has passed through the optical filter 2 passes through the liquid crystal display element 3 and the projection lens 4 to form an image on a screen (not shown). As a result, the color reproduction region of the formed image is enlarged, and the image becomes clearer.

  However, in the configuration of FIG. 4, the light reflected without being transmitted through the liquid crystal display element 3 returns to the optical filter 2, is reflected again by the optical filter 2, passes through the liquid crystal display element 3 and the projection lens 4, and There was a disadvantage of deteriorating the sharpness.

As an improvement measure, for example, as shown in Patent Document 1, there is a method of tilting the optical filter from a position perpendicular to the optical axis. FIG. 5 is a plan view showing the configuration of the projector when the optical filter 2 is tilted from the vertical position with respect to the optical axis, as in Patent Document 1. In the figure, the same components as those in FIG. In this configuration, when light reflected without being transmitted through the liquid crystal display element 3 tries to return to the optical filter 2, the optical filter 2 is reflected by the optical filter 2 because the optical filter 2 has an angle θ with respect to the optical axis 6. The light does not return to the display element 3, so that the sharpness of the image can be maintained.
JP 2004-94175 A

  In the above conventional method, a space for tilting the optical filter 2 with respect to the optical axis is required, and the entire optical system becomes large. Further, since the optical filter 2 is tilted by θ with respect to the optical axis, the light from the light source lamp 1 and the return light from the liquid crystal display element 3 are reflected by the optical filter 2 and emitted outside the optical system. For this reason, since the surrounding structure stores heat by light and the temperature rises, a cooling means such as a fan is required. For this reason, the size of the apparatus is further increased, and noise from the fan is also generated.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an optical device and a projector provided with an optical filter that can maintain the sharpness of an image without increasing the size of the device or requiring new cooling means. .

  An optical apparatus and a projector including the optical filter of the present invention includes a light source, an optical filter for reducing components other than red, green, and blue from the light components of the light source, and light that optically modulates an input video signal. The optical filter is disposed perpendicular to the optical axis of the light source and has a curvature surface.

  According to the present invention, it is possible to reduce the influence of reflected light by providing a curvature surface on an optical filter that realizes sharpening of an image, and the optical filter can be arranged perpendicular to the optical axis. Become. For this reason, there is no need for a space for tilting the optical filter from a position perpendicular to the optical axis, and there is an advantage that the entire optical system can be reduced in size while realizing a clear image.

  Furthermore, the heat storage and temperature rise of the structure around the optical system due to the reflected light can be suppressed, and therefore there is an advantage that a cooling means such as a fan becomes unnecessary, and noise can be reduced and the apparatus can be downsized.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

(Embodiment 1)
FIG. 1 is a plan view showing a configuration of an optical system of a projector according to an embodiment of the present invention, and the same components as those in the conventional example are given the same numbers.

  In the figure, 1 is a light source lamp, 5 is an optical filter for reducing components other than red, green and blue from the light from the light source lamp, and 3 is a liquid crystal display element which is a light modulation device for modulating an input video signal 4 represents a projection lens, and 6 represents an optical axis. In the figure, the light emitted from the light source lamp 1 passes through the optical filter 5, then passes through the liquid crystal display element 3, and then is enlarged by the projection lens 4 to form an image on a screen (not shown). .

  At this time, red, green, and blue light are transmitted by the optical filter 5 and yellow and cyan lights that are intermediate colors are reflected.

  As a result, the color reproduction region of the formed image is enlarged and the image becomes clearer.

  FIG. 2 is a diagram showing the shape of the optical filter 5 of the projector of the present invention. The optical filter 5 has an R2000 curvature surface 5 a with respect to the vertical surface of the optical axis 6.

  Although the curvature is R2000 in the present embodiment, R500 to R3000 are desirable. If R is too small, side effects occur in the optical performance, and if R is too large, no effect appears.

  FIG. 3 shows the reflection on the liquid crystal display element 3 when the optical filter 2 having no curvature surface is mounted (a) and when the optical filter 5 having the curvature surface in the embodiment of the present invention is mounted (b). It is the figure which showed distribution of the light ray of light.

  In FIG. 3B, the curvature surface 5a is provided on the opposite side (light source side) with respect to the liquid crystal display element 3, although it is difficult to discriminate due to the relationship with the overall size.

  In FIG. 3A, the reflected light 7 from the liquid crystal display element 3 returns to the optical filter 2 having no curvature surface, and the re-reflected light 8 from the optical filter 2 is condensed again at the position of the liquid crystal display element 3. The image is magnified by the projection lens 4 and the sharpness of the image is deteriorated.

  In FIG. 3B, the reflected light 7 from the liquid crystal display element 3 returns to the optical filter 5 having the curvature surface 5a, but the reflection direction of the re-reflected light 9 from the optical filter 5 is changed again by the curvature surface 5a. Light is not condensed at the position of the liquid crystal display element 3. For this reason, the influence by re-reflected light is reduced, so that the sharpness of the image can be maintained.

  Since the optical system including the optical filter 5 having such a curvature surface 5a is employed, the optical filter 5 for sharpening an image can be arranged perpendicular to the optical axis 6 of the optical system. The sharpness of the image is not deteriorated by tilting the optical filter.

  This eliminates the need to incline the optical filter 5 for sharpening the image with respect to the optical axis 6 and eliminates the need for an extra space for this purpose.

  Further, since the optical filter 5 is arranged perpendicular to the optical axis 6, the amount of light reflected by the optical filter 5 is emitted to the outside of the optical system is greatly reduced. Heat storage and temperature rise of the structure can be suppressed, and there is an effect that a cooling means such as a fan becomes unnecessary. Therefore, no noise is generated by the fan.

  Needless to say, a space for a cooling means such as a fan is unnecessary, and it goes without saying that this also helps to reduce the size of the apparatus.

  The optical device and projector provided with the optical filter according to the present invention can reduce the size and weight of the optical device and projector by not affecting the downsizing of the optical system without deteriorating the sharpness of the image. Can do. Further, since the heat storage and temperature rise of the structure around the optical system can be suppressed, the cooling capacity can be suppressed, noise can be reduced, and the optical device and projector provided with the optical filter for realizing the sharpening of the image Useful for.

The top view which shows the structure of the optical system of the projector in embodiment of this invention The figure which shows the shape of the optical filter of the projector in embodiment of this invention The figure which showed distribution of the light ray of the reflected light in the display element at the time of mounting | wearing with the optical filter which does not have a curvature surface, and the optical filter 5 which has a curvature surface in embodiment of this invention. A plan view showing a configuration of a projector provided with a conventional optical filter A plan view showing the configuration of a projector when a conventional optical filter is tilted with respect to the optical axis

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light source lamp 2 Optical filter which does not have a curvature surface 3 Liquid crystal display element 4 Projection lens 5 Optical filter which has a curvature surface 5a Curvature surface 6 Optical axis 7 Reflected light in the liquid crystal display element 8 8 Re-reflected light in the optical filter 9 Re-reflected light from the optical filter 5

Claims (4)

A light source; an optical filter for reducing components other than red, green, and blue from the light components of the light source; and a light modulation device that optically modulates an input video signal, wherein the optical filter is light of the light source. An optical device and a projector, which are arranged perpendicular to an axis, and at least one surface is a curvature surface. The optical apparatus and projector according to claim 1, wherein the curvature of the curvature surface of the optical filter is R500 to R3000. 3. The optical apparatus and projector according to claim 1, wherein the light source side is a curvature surface. 4. The optical device and projector according to claim 1, wherein the light modulation device is a liquid crystal display element.